Are Your Windows and Curtain Walls Performing as Specified?

If you're dealing with water leaking around windows, condensation forming on interior glazing surfaces, air drafts at curtain wall perimeters, or structural seals that have separated — your building is experiencing fenestration system failure, one of the most common performance complaints in commercial construction. Windows, curtain walls, storefronts, and skylights account for a substantial portion of building envelope performance issues because they involve complex interactions between glass, metal frames, sealants, gaskets, and the adjacent wall assembly.

ACE Building Envelope Design's AAMA fenestration performance testing evaluates installed window and curtain wall systems against the design standards they were specified to meet. Our FGIA/AAMA accreditation ensures that test results are accepted by manufacturers for warranty claims, by owners for acceptance documentation, and by attorneys for construction defect proceedings.

Fenestration failures can originate from manufacturing defects, installation errors, design specification inadequacy, or incompatibility between the fenestration system and the building's structural movement characteristics. ACE's forensic investigation methodology distinguishes between these causes — a critical determination for warranty claims and responsibility allocation. The FGIA performance standards referenced in our testing establish the benchmarks against which installed fenestration is evaluated.

Common Fenestration Failure Modes and Causes

Fenestration failures manifest in several distinct patterns. Water leakage at frame corners indicates either a manufacturing defect in the corner joint or installation damage during handling. Water at the sill typically points to inadequate sill pan flashing or weep system obstruction. Air infiltration around the frame perimeter suggests gaps between the fenestration unit and the rough opening that were inadequately sealed during installation. And condensation on interior glazing surfaces may indicate failed insulating glass units (IGU seal failure) or insufficient thermal performance for the building's climate zone.

Each failure mode requires different investigation and different resolution. ACE's forensic approach examines the fenestration system, the installation condition, and the design specification to determine which factor — or combination of factors — is responsible. This determination is essential for warranty claims because it identifies whether the manufacturer, the installer, or the specifying architect bears responsibility.

Window-to-Wall Integration and Perimeter Failures

The interface between the fenestration unit and the surrounding wall assembly is where most field failures occur. This perimeter condition must provide continuous water management, air barrier continuity, and thermal performance — all while accommodating differential movement between the fenestration frame and the building structure. Flashing and transition details at window heads, jambs, and sills must integrate the fenestration system into the wall's drainage plane and air barrier without creating pathways for water or air to bypass the weather barrier.

ACE's envelope design services address window-to-wall integration as a critical design element — not an afterthought left to the installer. Our forensic investigation experience has documented recurring patterns of perimeter failure that inform our design recommendations: missing sill pan flashings, incompatible sealant-to-membrane connections, and insufficient overlap at head flashing conditions are among the most common deficiencies we identify.

AAMA Performance Testing for Installed Systems

AAMA fenestration testing provides the definitive assessment of installed fenestration performance. ACE performs AAMA 501.1 (field water testing), AAMA 502 (condensation resistance), and AAMA 503 (voluntary specifications for field testing) procedures that evaluate whether installed systems meet their design performance ratings for water penetration resistance, air infiltration, and structural wind load capacity.

These accredited tests determine whether the installed performance matches the laboratory ratings specified in the contract documents. When it doesn't, the test data identifies where the system is failing and provides the measured evidence needed to pursue warranty claims or construction defect resolution. For high-rise buildings where curtain wall is the primary weather barrier, AAMA testing is especially critical at both the mockup and production stages.

Resolution Strategies for Fenestration Problems

Fenestration repair strategies depend entirely on the failure cause. Manufacturing defects typically require unit replacement under warranty. Installation deficiencies may be addressable through perimeter re-sealing, sill pan retrofit, or flashing correction without replacing the fenestration unit itself. Design specification issues — where the specified system was inadequate for the building's exposure conditions — may require system upgrade or supplemental protection measures.

ACE's forensic findings drive the repair specification, ensuring that the intervention addresses the actual cause. Our construction administration services oversee repair installation, and post-repair accredited testing verifies that the repaired system meets its performance requirements. For buildings with widespread fenestration issues, ACE develops phased repair programs that prioritize the most exposed or most damaged conditions.

Related Pages

← Back to Problems

Frequently Asked Questions